It’s just after 9 a.m. on a June morning in the small training room of the Steadman Hawkins Physical Therapy clinic in Englewood. Country tunes stream through overhead speakers as Loren Landow tells his client to stand atop a box, 18 inches tall, that he’s placed in front of her. It’s one of the final dry-land training sessions the two of them will have before the young swimmer heads off to her competition overseas. He instructs her to jump toward the ceiling 10 times, then drop to the floor and hold a core-strengthening plank position for one minute. The athlete’s mischievous half-glare/half-smile tells Landow she needs further explanation.

“The explosion is crucial for you to get off the…. What do they call the thing you jump off of into the pool?” he asks. “A platform? A box? A block?”

She gazes down from her perch toward Landow. At 6-foot-1, she’s as tall as some of the NFL players he’ll see later that afternoon. “Nope,” she says with a straight face. “When we’re ready to start the race, the announcer says, ‘Everyone get on your things.’?”

Landow rolls his eyes as she howls with laughter. A little fun is allowed; one of his primary goals is to balance the rigors of his prescribed training program with a bit of levity to lighten the athlete’s psyche. She stretches out, body flat, pressing on her toes and forearms in plank position as Landow asks, “What’s your plan for breakfast?”

“Ooohhh,” she squeals with delight. “Maybe my mom will make this omelet thing she made yesterday morning. It was soooo good.”

As the athlete starts her next set, Landow texts her mom to request the omelet he knows the teenager will need to replenish the calories she’s already burned. A few feet away, oblivious to the exchange, she holds another plank position while singing along with Keith Urban on the stereo. When she’s finished, Landow sends her home to rest before her afternoon workout. Nine weeks later, Landow’s client, Missy Franklin, would climb atop another box—this one a podium—after winning her fourth gold medal, her fifth medal overall, at the London Olympic Games.

Landow’s client list reads like a who’s who of elite athletes. In addition to Franklin, three-time X Games champion skier Bobby Brown goes to Landow for his own dry-land work. Olympic gymnast Alicia Sacramone enlisted Landow to help her return from a torn Achilles tendon she suffered at the 2011 World Championships, and current and former NFL players such as Chad Brown and Bo Scaife have used Landow to invigorate or revive their careers. Mixed Martial Arts (MMA) world champion Nate Marquardt trains with Landow three times a week. And in the minutes before the Denver Broncos kicked off against the Pittsburgh Steelers in the 2012 AFC Wild Card Game, quarterback Tim Tebow called Landow for a pregame mental boost. The two had been working together since the 2011 NFL lockout; later that January day, Tebow tossed the now-legendary 80-yard touchdown pass that beat the Steelers in overtime.

At Landow’s clinic, most of the jerseys, shorts, and framed action photographs on the wall are signed with variations of “couldn’t have done it without you” and “you’re the reason I’m here today.” Athletes who perform at world-class levels usually have the necessary talent; what some, maybe even most, of them lack is Landow’s perfectionist expertise. Any trainer can make you puke with endless, forced reps of sprints, push-ups, and godforsaken burpees. Landow—author of My Off-Season with the Denver Broncos: Building a Championship Team (While Nobody’s Watching), and a frequent presenter at personal-training conferences—is more of a professor.

Landow’s training philosophy derives from the theory of dynamic correspondence. Simply put, increasing the development of force (strength), while decreasing the time it takes to produce that force (speed), results in greater efficiency. Building upon each unwasted effort, Landow’s athletes become stronger, faster, and better.

They also tend to suffer fewer injuries due to his method of tailoring training programs to specific time and pressure calibrations that mirror the demands they’ll face in competition. Landow’s NFL players don’t run laps around the field, for example, because that’s a waste of time. Instead, he drills into them the keen understanding of how to physically explode for the five or six seconds each play requires, then rest until the next snap. And Landow’s MMA fighters must tap into multiple energy systems as they exercise in 15- to 20-second bursts within five-minute rounds, expending a similar amount of controlled but explosive energy—in a similar way—that they would during an actual bout.

Everything the 39-year-old teaches—including biology, physiology, and chemistry—most trainers and athletes would rather leave in a textbook. Landow painstakingly explains the science behind the exercises, how everything from a stutter-step past a defender to sticking a landing off the vault works, and why it matters. It’s an attention to detail that results, for Landow, in 12-hour workdays of individual sessions and group workouts—often with no lunch. (Landow demands similar commitment from his clients; he often asks them to consider whether a momentary impulse—to skip or cut short a workout, or to sleep in just this once—is worth sacrificing their long-term personal goals.)

It’s not just the intricate knowledge that appeals to these athletes; it’s also the person who’s dropping the knowledge on them. Marquardt, the world-champion MMA fighter, says he’s learned to trust that Landow is “training Nate for Nate,” not for a team or for his own personal gain. “He is a genius when it comes to the science behind his work,” Marquardt says. “[He understands that] I don’t go into the cage to lift weights and run sprints. I go into the cage to fight. My hardest training should mimic what I do in competition.”

Landow graduated from Westminster High School as a multisport athlete. He majored in exercise science at the University of Northern Colorado and moved right into a training career, tending at first to everyday athletes trying to rehab an injury or get back in shape. Although Landow acknowledges he’s not as fast or as strong as the athletes he trains, he says he’s not far off. Before anyone starts an exercise, Landow first demonstrates it—precisely. “I have to show these elite-level athletes I can do it better than them,” he says. “I really work on my craft a lot so I get that buy-in. If I show them that at 39 years old I can be very, very athletic and stay in shape, that’s when they realize there’s something here.”

Every minute of Landow’s free time, except for his occasional indulgence in a round of golf, is directed toward his family: wife Michelle, a physical therapist, and their two daughters, nine-year-old Taylor and six-year-old Morgan. Landow calls his wife “a saint” for allowing him to pursue his time-consuming career, though it does have benefits—such as when Missy Franklin showed up at Taylor’s Olympic-themed birthday party. “There are bonuses, because my family gets to meet a lot of these athletes and spend time with these special people,” says Landow, adding that Taylor has already declared her intentions to win Olympic gold in gymnastics. “It creates a nice win-win for everybody.”

He credits his children with showing him what’s worth a meltdown with his clients and what’s not. “Having kids taught me patience and to pick my battles,” he says. “Is the next rep on the bench as important as the handshake and the hug I give you after the session? I’m a big believer in letting these athletes know they have someone in their corner. They have coaches who are there for them on their team, but as soon as they are done, they’re gone. I’m a coach for life.”

Sleepy-eyed football players meander from tinted-window SUVs onto the Regis High School football field. The sky on this July morning is spectacularly blue as Denver heads toward another 90-degree day. With less than a week before NFL teams start training camp, 13 players from the Broncos, the New York Giants, and several other teams, along with unsigned rookies and a kid hoping to take over the quarterback spot for Grand Junction High School, gather around Landow.

Although he sometimes hosts 30 to 50 athletes in his workouts, today a few stayed home to hold their families a little tighter. The night before, the Aurora theater shootings had taken 12 lives inside the same city boundaries where these hopefuls now stand waiting for a workout. Landow pauses to make sure each of the athletes’ friends and families is safe, and he reminds them to relish the job they get to do each day.

Today will be an “easy” workout: an hour of footwork drills, receivers running routes with quarterbacks, and weight lifting back at the clinic. Landow’s dynamic stretching exercises—like lunges, leg kicks, and jump squats—induce an initial sweat, and players begin to shed layers of workout clothes before the quick, precise footwork begins. He calls for the carioca drill, in which players rapidly tiptoe while swiveling their hips as they move back and forth over a 20-yard course. Landow scrutinizes and critiques each of their tiny steps, and doesn’t hesitate to call out a flub. “Don’t bullshit your way through this,” he says. “Finish all the way through!”

The entire workout mimics a 60-minute football game—intense bursts of activity followed by a half-minute or so of rest—almost to the second. When it’s over, the exhausted players veer toward their water bottles. Although Landow knows some of these men won’t make an NFL team, he follows all his athletes like a proud parent, waiting to hear which of his college football players have been selected in the NFL draft, watching Franklin’s medal count pile up, or sitting cage-side during a Marquardt bout. It’s all driven by his desire to make sure every detail is accounted for before Landow sends them off to pursue their shared quest for athletic excellence. “I offset my sense of responsibility with preparation,” Landow says. “I have to know when they’re ready for me to push them out of the nest.”